- save_pdf(): constify path parameter and routine no longer frees it.
Follow latter change in pdf_end(), nsgtk_PDF_set_pass() and nsgtk_PDF_no_pass()
- pdf_printer: constify
- last_clip_x0, last_clip_y0, last_clip_x1, last_clip_y1, in_text_mode, text_mode_request: make static
- pdf_doc: free previous PDF document if previous save attempt failed.
- set PDF Creator entry based on our user_agent_string().
* other minor changes.
svn path=/trunk/netsurf/; revision=5452